﻿#pragma once

class PID
{

public:
// Constants used in some of the functions below
#define AUTOMATIC 1
#define MANUAL 0
#define DIRECT 0
#define REVERSE 1
#define P_ON_M 0
#define P_ON_E 1

    // commonly used functions **************************************************************************
    PID(double *Input, double *Output, double *Setpoint,
        double Kp, double Ki, double Kd, int POn, int ControllerDirectio); // * constructor.  links the PID to the Input, Output, and Setpoint.  Initial tuning parameters are also set here (overload for specifying proportional mode)

    PID(double *Input, double *Output, double *Setpoint,
        double Kp, double Ki, double Kd, int ControllerDirectio); // * constructor.  links the PID to the Input, Output, and Setpoint.  Initial tuning parameters are also set here

    void SetMode(int Mode); // * sets PID to either Manual (0) or Auto (non-0)

    bool Compute(); // * performs the PID calculation.  it should be
                    //   called every time loop() cycles. ON/OFF and
                    //   calculation frequency can be set using SetMode
                    //   SetSampleTime respectively

    void SetOutputLimits(double, double); // * clamps the output to a specific range. 0-255 by default, but
                                          //   it's likely the user will want to change this depending on
                                          //   the application

    // available but not commonly used functions ********************************************************
    void SetTunings(double, double, // * While most users will set the tunings once in the
                    double);        //   constructor, this function gives the user the option
                                    //   of changing tunings during runtime for Adaptive control
    void SetTunings(double, double, // * overload for specifying proportional mode
                    double, int);

    void SetControllerDirection(int); // * Sets the Direction, or "Action" of the controller. DIRECT
                                      //   means the output will increase when error is positive. REVERSE
                                      //   means the opposite.  it's very unlikely that this will be needed
                                      //   once it is set in the constructor.
    void SetSampleTime(int);          // * sets the frequency, in Milliseconds, with which
                                      //   the PID calculation is performed.  default is 100

    // Display functions ****************************************************************
    double GetKp();     // These functions query the pid for interal values.
    double GetKi();     //  they were created mainly for the pid front-end,
    double GetKd();     // where it's important to know what is actually
    int GetMode();      //  inside the PID.
    int GetDirection(); //

private:
    void Initialize();

    double m_dispKp; // * we'll hold on to the tuning parameters in user-entered
    double m_dispKi; //   format for display purposes
    double m_dispKd; //

    double m_kp; // * (P)roportional Tuning Parameter
    double m_ki; // * (I)ntegral Tuning Parameter
    double m_kd; // * (D)erivative Tuning Parameter

    int m_controllerDirection;
    int m_pOn;

    double *m_input;    // * Pointers to the Input, Output, and Setpoint variables
    double *m_output;   //   This creates a hard link between the variables and the
    double *m_setpoint; //   PID, freeing the user from having to constantly tell us
                        //   what these values are.  with pointers we'll just know.

    unsigned long m_lastTime;
    double m_outputSum, m_lastInput;

    unsigned long m_sampleTime;
    double m_outMin, m_outMax;
    bool m_inAuto, m_pOnE;
};